Field of the Invention
This invention relates to solar cell module having improved collection efficiency of solar panels and a method of fabricating the same. Particularly, this invention relates to solar cell module wherein transmission gratings are used for splitting the the incident light wavelengths to different bands and directing such different wavelengths towards the the face of different solar cells according to their optimum wavelengths for solar power generation , thereby improving the overall cell efficiency of the module. Background of invention -
The average solar cell efficiency at present is around 17 %, This is because, substantial amount of the incident solar radiation is lost as it passes through the gaps of the active substrate of the solar cells in the module and substantial amount of the photons remain un utilized. This results in lesser number of electron - hole pair generation and hence less power generation. Efficiency of solar cells, pertaining to generation of power, is dependent on the materials used and on specific wave lengths of the incident light. Presently, there exists a trade-off between cost of manufacturing of the cells and efficiency. Cost involved in producing energy, using solar cell can be compensated, if the efficiency of the solar cell can be increased. Different methods and different materials, have been employed for such purpose. For example, an attempt has been made to increase the incident ray collection efficiency, by using tandem solar cells. Total efficiency of the solar cell module can of course be improved, by using bi-facial solar cells . To utilize the bi-facial cell effectively it is required to allow sun light fall on the both sides of the cell at the same time. Different methods have been employed to achieve this object to but satisfactory results could not be achieve in production environment.
It is known to use holograms to reflect the light on to backside of the cell. The production of these holograms is not a very user-friendly process and not satisfactory in making them at mass production level.
Using concentrator elements such as light guide, with Solar cell also improves the total efficiency of the system. The use of concentrator reduces the amount of photovoltaic material being used which in turn, reduces the cost. However, this technology generated too much heat on the solar cells, which adversely affected its efficiency. Furthermore, this technology has not been able to achieve the goal of generation of power at optimum cost, to the fullest

extent, primarily due to deficiency in improving the collection efficiency of the solar panels, and this has been the principal drawback of all hitherto known technologies. Accordingly, there has been a long felt need to increase the efficiency of solar cell modules, by improving the collection efficiency of the solar panels, so that energy can be obtained at optimum cost. The present Invention is directed to achieve this primary object and to other objects, as stated hereinafter. Objects of the Invention,
It is an object of the invention to provide an improved solar cell module having improved collection efficiency of solar panels.
It is another object of the present invention to provide a solar cell module with transmission gratings which can split the incident wave length into different wavelengths and using different solar cells according to their optimum wavelengths for solar power generation.
It Is yet another object of the present invention to a capture a wide spectrum of the incident solar ray and splitting the wavelengths into different bands according to the requirement to extract optimum efficiency from different solar cells.
It is yet further object of the invention to improve the efficiency of the solar cell module.
It is another object of the invention to reduce the cost of generation of electricity from the solar cell module.
It is yet another object of the invention to provide a feasible and easily replicable solution to improve the efficiency of the solar panels.
It is a further object of the present invention to fabricate a solar cell module having improved collection efficiency of solar panels.
The above objects and other aspects of the present invention will be clear from the following description which is purely by of understanding and not by way of any sort of limitation.
Summary of the Invention
Accordingly the present invention provides an improved solar cell module for converting solar energy into electrical energy , including transmission grating of suitable material and a plurality of interconnected solar cells wherein the solar cells are located beneath said

transmission grating so that the diffracted bands of light can be made to fall on respective solar cells, specifically selected to ensure suitability for optimum use of the particular wave length for producing solar power, whereby the collection efficiency of the solar panels is increased and wide spectrum of light is utilized, thereby facilitating increase in efficiency of the solar cell module.
In accordance with preferred embodiments of the solar cell module according to the invention
-the grating is pre-fabricated to reflect particular selected band of wavelength towards the
respective solar cells.
-the transmission grating has grooves ruled onto a transparent material, such as glass or
Perspex.
-the transmission grating is made of different transparent as well as reflective materials.
-the transparent material can be made reflective by metal deposition, such as aluminium oxide.
-the selection of photovoltaic material can be made, depending upon the wavelength diffracted by the shape of the grating.
-wherein solar cells with different absorption peak is selected so that maximum photon can be utilized in the electron-hole pair generation, thereby increasing the efficiency, -the solar cells are connected in series.
-multi-crystalline solar cells used in the solar cell module.
The present invention also provides a method for fabricating an improved solar cell module for converting solar energy into electrical energy , including connecting a plurality of interconnected solar cells and selecting transmission grating of suitable material, wherein said method comprises, disposing the solar cells beneath said transmission grating,so that the diffracted bands of light falls on respective solar cells, specifically selected to ensure suitability for optimum use of the particular wave length for producing solar power, whereby

the collection efficiency of the solar panels is increased and wide spectrum of light is utilized, thereby facilitating increase in efficiency of the solar cell module.
Brief Description of the Accompanying Drawings
The nature and scope of the present invention will be better understood from the accompanying drawings which are purely by of illustration and not by way of any sort of limitation. In the accompanying drawings:
Fig 1 illustrates a preferred embodiment of the solar cell module in accordance with the invention showing splitting of incident light into different wave lengths.
Fig 2 is an exploded view of an exemplary diffraction grating surface illustrating efficient diffraction of incident beam in accordance with the invention.
Detailed Description of the Invention
As stated before there has been a long felt need to increase the efficiency of solar cell modules, by improving the collection efficiency of the solar panels, so that energy can be obtained at optimum cost. The present Invention aims to solve the problem by using transmission gratings on the solar cell modules .
A transmission grating has grooves ruled onto a transparent material, such as glass or Perspex, so that a beam of light passed through the grating is partly splits into sets, or orders, with spectra on either side of it; the blue light is diffracted the least and the red light the most in each order. The following equation is pertinent in this respect.
a(sin I - sin D) = mA
where m = an integer, and is the order of diffraction
a = distance between grating normals
I = angle of incidence
D = angle of diffraction
A = wavelength of the incident beam
The splitting of incident light beam is shown in figure 1.

The transmission diffraction grating can be made of different transparent as well as reflective materials. The Transparent material can be made reflective by doing metal deposition, such as aluminium oxide . The grating can be fabricated to reflect particular band of wavelength towards the solar cell.
The selection of photovoltaic material can be made depending upon the wavelength diffracted by the shape of the grating. Use of solar cells with different absorption peak is possible so that maximum photon can be utilized in the electron-hole pair generation, thereby increasing the efficiency. The invention provides for use of simple optics in order to get maximum collection incident solar radiation.
In case of present invention transmission grating solar cells are placed below the grating so that the diffracted bands of light can be made to fall on specific solar cells suitable for optimum use of the particular wave length for producing solar power. This ensures to achieve the goal of the invention namely, improving the collection efficiency of the solar panels, so that energy can be obtained at optimum cost. Normally, multi-crystalline solar cells used in the solar cell module . The different solar cells are connected in series or otherwise known to persons skilled in the art for collection of solar power generated from different cells.
The inventive solar cell module of the present invention provides for increased efficiency of the solar cells, by generating maximum power at optimum cost and therefore it has industrial applicability.
The novel concept of the invention is in increasing the collection efficiency of the panel and use of wide spectrum of light. The present invention uses simple optics in order to get maximum collection of incident solar radiation. The efficiency of the system is increased and the cost of the system is reduced.
The instant invention has been described with the help of exemplary embodiments only . Various modifications and alterations can be thought of without departing from of the spirit and scope of the invention as defined in the appended claims.

WE CLAIM
!.An improved solar cell module for converting solar energy into electrical energy , including transmission grating of suitable material and a plurality of interconnected solar cells wherein the solar cells are located beneath said transmission grating so that the diffracted bands of light can be made to fall on respective solar cells, specifically selected to ensure suitability for optimum use of the particular wave length for producing solar power, whereby the collection efficiency of the solar panels is increased and wide spectrum of light is utilized, thereby facilitating increase in efficiency of the solar cell module.
2.The solar cell module as claimed in claim 1 wherein the grating is pre-fabricated to reflect particular selected band of wavelength towards the respective solar cells.
3.The solar cell module as claimed in claim 1 or 2 wherein the transmission grating has grooves ruled onto a transparent material, such as glass or Perspex,
4. The solar cell module as claimed in claim 2 wherein the transmission grating is made of different transparent as well as reflective materials.
5. The solar cell module as claimed in claim 4 wherein the transparent material can be made reflective by metal deposition, such as aluminium oxide.
6.The solar cell module as claimed in any preceding claim wherein the selection of photovoltaic material can be made, depending upon the wavelength diffracted by the shape of the grating.
7. The solar cell module as claimed in any preceding claim wherein solar cells with different absorption peak is selected so that maximum photon can be utilized in the electron-hole pair generation, thereby increasing the efficiency.
8. The solar cell module as claimed in any preceding claim wherein the solar cells are connected in series.

9. The solar cell module as claimed in any preceding claim wherein multi-crystalline solar
cells used in the solar cell module.
10. A method for fabricating an improved solar cell module for converting solar energy into
electrical energy , including connecting a plurality of interconnected solar cells and selecting
transmission grating of suitable material, wherein said method comprises, disposing the solar
cells beneath said transmission grating, so that the diffracted bands of light falls on
respective solar cells, specifically selected to ensure suitability for optimum use of the
particular wave length for producing solar power, whereby the collection efficiency of the
solar panels is increased and wide spectrum of light is utilized, thereby facilitating increase
in efficiency of the solar cell module.
Dated this the 21st day of February 2008
V